The work outlined in this grant proposal should allow us to obtain fundamental knowledge about the metabolism of the enzyme glutamine transferase (synthetase) (GS) in the retina. Projects outlined will include: the isolation of the steroid receptor; the isolation of steroid-resistant mutant cell lines; the isolation of the insulin receptor; the isolation of GS mutant cell lines; the study of the control of GS activity and the changes found with aging and diabetes using radioimmunoassays.